Display systems generally may be grouped into direct view displays and projection displays. Direct view displays allow direct observation of the object plane by the user of the direct view display system. Projection display systems project light from an object plane onto an image plane such that the user of the projection display system views light from the image plane. The image plane of a projection display system may be a front projection surface, in which the display system and the viewer are located on the same side of the image plane, or a rear projection surface, in which the display system and the viewer are located on opposite sides of the image plane. Unless otherwise stated, the concepts taught herein apply to both front and rear projection display systems.
Projection display systems rely on light from the object plane. This light may be emitted from a display panel located at the object plane, for example by a plasma discharge panel, an array of light emitting diodes, or the phosphor screen of a cathode ray tube, or any other source of light. Alternatively, the light may be transmitted or reflected by a display panel located at the object plane, for example by a micromirror array, a transmissive liquid crystal device, a reflective liquid crystal device, a photographic slide, or any physical object capable of reflecting incident light.
Modern display systems have made tremendous advances over the last ten to twenty years in terms of color fidelity, image brightness, image contrast, image distortion, and image size. Consumer expectations for display systems continue to increase. As such, it is very desirable to produce very high quality images from very small, low-cost display systems that are easy to use and adapt well to typical viewing environments.